Airhead rear main seal install: oil or no oil?

spartanman · 06-14-2010, 07:02 PM

As I understand it, Part No. 11 11 1 261 739 is an upgraded rear main seal design. It looks remarkably different than the original spring-actuated lip seal. I've read it has a teflon sealing surface and therefore should be installed dry. This is consistent with my experience on Cummins 12V diesel engines that use teflon main seals front and rear. I've also read that the BMW seal should first be soaked in hot oil before installation. What's been your experience? Thanks.

wirewrkr · 06-14-2010, 07:15 PM

I've installed that teflon seal 10 times in as many years. I've never had one leak. I put mine in dry and dry. no soaking, no wetting.

Hawk Medicine · 06-14-2010, 07:46 PM

Dry.

Infracaninophile · 06-14-2010, 08:05 PM

Matt Parkhouse did mine for me for while I watched (in my basement). He massaged it a bit (not sure why) and stuck it in there. Dry.

T.

bmwrench · 06-14-2010, 08:14 PM

The "massaging" is to shape the lip. This prevents the lip from tearing as the flywheel goes on.

Beemerguru · 06-14-2010, 09:11 PM

Easiest way is to install the seal on the "guide ring" for a couple hours. That lets the seal naturally conform to the shape when you install everything.

Also make REAL sure the seal goes in dry and straight (use a round disc with holes for the flywheel bolts) as a pusher. If you see some shavings on the side of the disk when you finish pushing it in flush, you increase the likely hood of a later leak.

spartanman · 06-15-2010, 03:51 AM

Dry it is. Thanks all for the help. Much appreciated. Beemerguru: I borrowed an installation tool like the one you describe. Seal went in clean and straight.

jtwind · 06-15-2010, 04:25 AM

Mostly good advice. The new seals are something like the 4th generation and do not need oil or forming. Put them in dry, square and to the right depth and you are in business.

Beater · 06-15-2010, 05:23 AM

I did it dry. No leaks, no errors, and I have about 2K miles since the service.

AliBaba · 06-15-2010, 05:42 AM

Quote:

Originally Posted by spartanman

As I understand it, Part No. 11 11 1 261 739 is an upgraded rear main seal design.

Hmm, isn't 11 11 1 338 342 the new one?

wirewrkr · 06-15-2010, 07:27 AM

Quote:

Originally Posted by AliBaba

Hmm, isn't 11 11 1 338 342 the new one?

Yes, this is the current part number.
When BMW changes part numbers (which happens a lot) it doesn't always mean the part itself has changed.
this the tool that I have been using. a pieces of nylon that I spun up in the lathe. That and a hammer and it's a snapperoo!

Robert

coastranger · 06-15-2010, 11:11 AM

so what happens if it goes in wet

wirewrkr · 06-15-2010, 06:47 PM

Quote:

Originally Posted by coastranger

so what happens if it goes in wet

Some say that is how they do it and it works fine.
I don't care to tempt fate when it comes down to having to do a job twice.
Whatever you want to do, do it.

jtwind · 06-16-2010, 06:50 AM

Quote:

Originally Posted by coastranger

so what happens if it goes in wet

It wouldn't hurt if if you smear alittle oil on the edges of the seal. It's going to see oil sooner or later.

RecycledRS · 06-16-2010, 06:57 AM

Not knowing any better at the time I put mine in wet. Seal is working fine with 2500 miles so far.

06-14-2010, 07:02 PM	#1
spartanman ^OP regret minimizer Joined: Oct 2009 Location: NE Ohio Oddometer: 641	Airhead rear main seal install: oil or no oil? As I understand it, Part No. 11 11 1 261 739 is an upgraded rear main seal design. It looks remarkably different than the original spring-actuated lip seal. I've read it has a teflon sealing surface and therefore should be installed dry. This is consistent with my experience on Cummins 12V diesel engines that use teflon main seals front and rear. I've also read that the BMW seal should first be soaked in hot oil before installation. What's been your experience? Thanks.

06-14-2010, 07:15 PM	#2
wirewrkr the thread-killer Joined: May 2008 Location: HIGH desert Oddometer: 4,297	I've installed that teflon seal 10 times in as many years. I've never had one leak. I put mine in dry and dry. no soaking, no wetting. __________________ www.wirewerkes.com KILL YOUR TELEVISION !!!!

06-14-2010, 07:46 PM	#3
Hawk Medicine Coyote's Brother Joined: Jun 2008 Location: NOR CAL Oddometer: 3,299	Dry. __________________ Hawkdude Hate rots the pocket that carries it.

06-14-2010, 08:05 PM	#4
Infracaninophile Finding My Way.. $Infracaninophile's Avatar$ Joined: Sep 2001 Location: New England, USA Oddometer: 7,506	Matt Parkhouse did mine for me for while I watched (in my basement). He massaged it a bit (not sure why) and stuck it in there. Dry. T.
$Infracaninophile is offline$

06-14-2010, 09:11 PM	#6
Beemerguru Beemerguru...G/S guy Joined: Nov 2006 Location: Foster City, CA Oddometer: 640	Easiest way is to install the seal on the "guide ring" for a couple hours. That lets the seal naturally conform to the shape when you install everything. Also make REAL sure the seal goes in dry and straight (use a round disc with holes for the flywheel bolts) as a pusher. If you see some shavings on the side of the disk when you finish pushing it in flush, you increase the likely hood of a later leak. __________________ Greg Hutchinson BMW Club of Northern California, Ambassador, BMW MOA, Vice President Vintage BMW Club http://gregsgssite.shutterfly.com/

06-14-2010, 08:14 PM	#5
bmwrench Beastly Adventurer Joined: Nov 2006 Oddometer: 1,483	The "massaging" is to shape the lip. This prevents the lip from tearing as the flywheel goes on.

06-15-2010, 03:51 AM	#7
spartanman ^OP regret minimizer Joined: Oct 2009 Location: NE Ohio Oddometer: 641	Dry it is. Thanks all for the help. Much appreciated. Beemerguru: I borrowed an installation tool like the one you describe. Seal went in clean and straight.

06-15-2010, 04:25 AM	#8
jtwind Wisconsin Airhead Joined: Nov 2004 Location: Madison WI Oddometer: 3,451	Mostly good advice. The new seals are something like the 4th generation and do not need oil or forming. Put them in dry, square and to the right depth and you are in business. __________________ JT www.northwoodsairheads.com www.jefftrappwindsors.com "Between two explanations, choose the clearest; between two forms, the most elementary; between two expressions, the shortest." Between two motorcycles the simplest (DW) Eugeni d' Ors (1881-1954); Spanish writer.

06-15-2010, 05:23 AM	#9
Beater Scope Creep's Victim Joined: Sep 2009 Location: Decatur, GA, USA Oddometer: 2,289	I did it dry. No leaks, no errors, and I have about 2K miles since the service. __________________ Fred '85 R80RT G/Sified '91 R100GS Bumblebee Airhead Zen: Ride-Maintain-Repair-Ride On.

06-15-2010, 11:11 AM	#12
coastranger Gnarly Adventurer Joined: Jun 2009 Location: coast range oregon Oddometer: 430	so what happens if it goes in wet

06-16-2010, 06:57 AM	#15
RecycledRS Along for the ride Joined: Nov 2008 Location: Vancouver Island Oddometer: 914	Not knowing any better at the time I put mine in wet. Seal is working fine with 2500 miles so far. __________________ __________________________________________ "There's a fine line between a skinning and a shearing"

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: .
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode